1. Field of the Invention
The present invention control apparatus generally relates to servo control systems and, more particularly, to those adapted for machine control systems. The term "machine" as employed herein broadly refers to any physical system performing work functions such as machine tools, process valves, optical devices, temperature regulators, motors, fluid controllers, etc. The term "machine element" refers to any element of such a "machine" . The term "numerical control" refers to the control by number commands as performed by electronic devices.
2. Prior Art
The automation of machine control has lead to increased efforts to provide an alternative to those systems described by the prior art. Conventional servo mechanisms are well known in the art as elements of systems used to position a machine or other device with an adequate degree of accuracy. Typically, a position sensitive device detects the position or movement of the machine or other apparatus being monitored. A feedback signal source provides a signal determined by the position sensitive device. The feedback signal is compared to the command signal to provide an error signal that is employed in the servo mechanism to alter the position of the machine until the feedback and command signals are equal. The conventional servo mechanism loop is based upon analog signal processing. Analog signal processing provides efficient but expensive hardware implementation to provide continuous control over a machine tool or other type of devices.